efficacious efficacious  /ˌɛ fə ˈkeɪ ʃəs/


  1. (adj) marked by qualities giving the power to produce an intended effect
  2. (adj) producing or capable of producing an intended result or having a striking effect


Derived Word(s)


  1. Kiehl's may be global now, but it hasn't strayed from the simple, efficacious products that made it famous.
  2. When it was finally recognized for what it was the most efficacious life-saving drug in the world penicillin would alter forever the treatment of bacterial infections.
  3. This proved very efficacious in Iraq, especially in urban areas.



  1. "We will have a review at the end of this year to see if the strategy has been efficacious," Obama told il Corriere.
    on Jul 8, 2010 By: Barack Obama Source: Reuters Canada

  2. "Which borders do we close, do we close the Canadian border too? Do we close flights coming from countries in Europe where it's been identified now? We're told that is not an efficacious use of our effort. We should be focusing on mitigation,"...
    on Apr 30, 2009 By: Joe Biden Source: guardian.co.uk

  3. The anti-abortion conditions "have undermined efforts to promote safe and efficacious family planning programs in foreign nations," Clinton said.
    on Jan 20, 2009 By: Bill Clinton Source: WND.com

Word of the Day
anachronistic anachronistic
/ə ˌnæ krə ˈnɪ stɪk /